As for the idea that no one needs backflow prevention on account of supply pressure is always going to be there.......

What about that idea? You trailed off. It would benefit everyone, including myself if you can poke some holes in the rest of what I said, if you can.

You've already made your point about the backflow preventer multiple times. If the government agencies/regulators/whoever were as concerned as you are about the backflow preventer, they wouldn't allow Rain Birds DIY kit on the shelves.